A typical data system may have multiple tiers of storage. Higher tier storage devices may include high performance disks that provide faster access times and other benefits. Lower tier storage devices may include generic disks that are able to store data cheaply.
Tiering storage generally enhances the efficiency of data systems. For example, not all files are accessed frequently. Files that are accessed frequently may be stored on higher tier storage to allow for quick access. Files that are accessed infrequently may be stored on lower tier storage for economic reasons.
Deduplication may further enhance the efficiency of data systems. Deduplication generally involves storing only a single instance of data, or a segment of data. Since many files may share common data segments, performing deduplication on one or more tiers of storage may potentially result in substantial disk savings.
Files typically do not stay in the same tier for prolonged periods of time. Some files may lose importance, causing them to be moved to a lower tier storage. Similarly, some files may gain importance, causing them to be moved to a higher tier storage. Unfortunately, moving files, or data, between different tiers involves moving the whole file or data. This results in the loss of efficiency provided by deduplication.
There is a need, therefore, for an improved method, article of manufacture, and apparatus for protecting and accessing data in data systems.